Contents

It is unknown exactly how many ships the Forerunners had in their fleet, but given that a single AI would take personal command of a core fleet alone of one thousand ships, it is fair to assume that the Forerunner fleet consisted of many thousands of ships, though this number was severely whittled down over three centuries of war. During the course of the war, the Forerunner fleet attempted to prevent the Flood from landing on the surface of various planets, and when the Flood invariably did, the Forerunner Navy's main concern was to evacuate as many civilians as possible.

As the Forerunners realized that they had no chance of militarily winning the war, and as the Flood closed in on the Maginot Sphere, they created a master AI, 032 Mendicant Bias, to coordinate all of their strategic movements and grapple with the Gravemind itself. 032 Mendicant Bias was given a personal fleet of a thousand core capital ships. However, direct contact with the Gravemind caused 032 Mendicant Bias to turn rampant, and it quickly turned on its creators.

032 Mendicant Bias led its fleet through the Maginot Sphere, where it encountered three entire fleets of Forerunner warships led by Offensive Bias. The following encounter was quite possibly the largest battle ever seen by the galaxy ensued between the two opposing sides. At this point, IsoDidact, overall commander of the remaining Forerunner Navy, fired the Halo Array. Although it killed all the surviving Forerunners, it also neutralized 032 Mendicant Bias's giant Flood-controlled fleet, which had until this point, vastly outnumbered Offensive Bias. With the odds much more even, Offensive Bias managed to defeat the rampant AI's remaining core ships and attempted to deliver 032 Mendicant Bias to the Ark for study.[1]

What happened to the few surviving Forerunner ships after this is unknown, but without any Forerunners to guide them, some of them may have crashed onto various objects and were later found by the races of the Covenant, some utilizing the ships' advanced technology. For example, the Forerunner dreadnought was used to power the Covenant capital city of High Charity.[2]

Based on what was seen of them, Forerunner vessels were massive and extremely well protected and powered.

A single Keyship could power a structure the size of an entire moon;[3] and this only required a fraction of its total power output.[2] In a UNSC naval assault against the Covenant Loyalists in the Battle of Voi, three UNSC frigates fired their Magnetic Accelerator Cannons at the Forerunner dreadnought but it remained intact.[4] This makes it even more powerful than a Covenant supercruiser, which could only barely take the impact of three special light MAC rounds and five hundred Archer missiles. However, it has never been seen to use its actual weapons. The Forerunner dreadnought can combine their fire into a large singular beam capable of slicing a ship in two, before causing a massive explosion.[5]

Keyships such as the Forerunner dreadnought were used to open gateways to the Ark and to transport lifeforms away from the Array's effect, as well as back to their homeworlds. They also possessed powerful shielding and weaponry.[1][2]

Fortress-class vessels such as the "Deep Reverance" were the single largest ships of war the Forerunner had at their disposal. They measured 50 km in length, had a huge hemisphere at the front, a series of layered platforms equipped with launch bays and gun mounts in the mid level and a long weapon studded tail. At their widest they measured 10 km and could carry hundreds of thousands of the "Warrior Cast" of Forerunner into battle.

The Forerunners were also known to have smaller fighter-class ships. Several of the Fortress-class vessels were forced to deploy large squadrons of these fighters in order to repel Sentinels sent by 032 Mendicant Bias to protect the Halo's during the siege of the Forerunner Capital.

Council members of the Forerunners had their own specific class of vessel. The "Seedling Star" was one specific ship used by the council, it was said to eclipse all but the weapons of any ship allocated to the Warrior-Servants in every way. At the cutting edge of Forerunner science, these ships were incredibly fast, able to complete long distance slipspace jumps in just 2 hours.